ASTM E235/E235M-19
Standard Specification for Type K and Type N Mineral-Insulated, Metal-Sheathed Thermocouples for Nuclear or for Other High-Reliability Applications

Standard No.

ASTM E235/E235M-19

Release Date

2019

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM E235/E235M-23

Latest

ASTM E235/E235M-23

Scope

1.1 This specification covers the requirements for simplex, compacted mineral-insulated, metal-sheathed (MIMS), Type K and N thermocouples for nuclear or other high reliability service. Depending on size, these thermocouples are normally suitable for operating temperatures to 1652 °F [900 °C]; special conditions of environment and life expectancy may permit their use at temperatures in excess of 2012 °F [1100 °C]. This specification was prepared to detail requirements for this type of MIMS thermocouple for use in nuclear environments, but they can also be used for laboratory or general commercial applications where the environmental conditions exceed normal service requirements. The intended use of a MIMS thermocouple in a specific nuclear application will require evaluation of the compatibility of the thermocouple, including the effect of the temperature, atmosphere, and integrated neutron flux on the materials and accuracy of the thermoelements in the proposed application by the purchaser. 1.2 This specification does not attempt to include all possible specifications, standards, etc., for materials that may be used as sheathing, insulation, and thermocouple wires for sheathed-type construction. The requirements of this specification include only the austenitic stainless steels and other alloys as allowed by Specification E585/E585M for sheathing, magnesium oxide or aluminum oxide as insulation, and Type K and N thermocouple wires for thermoelements (see Note 1). 1.3 General Design—Nominal sizes of the finished thermocouples shall be 0.0400 in., 0.0625 in., 0.125 in., 0.1875 in., or 0.250 in. [1.000 mm, 1.500 mm, 3.000 mm, 4.500 mm, or 6.000 mm]. Sheath dimensions and tolerances for each nominal size shall be in accordance with Table 1 and Figs. 1 and 2. The measuring junction styles for thermocouples covered by this specification are as follows: 1.3.1 Style G2 (grounded)—The measuring junction is electrically connected to its conductive sheath, and 1.3.2 Style U2 (ungrounded)—The measuring junction is electrically isolated from its conductive sheath and from reference ground. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not exact equivalents or conversions; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ASTM E235/E235M-19 Referenced Document

• ASTM A262 Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
• ASTM E112 Standard Test Methods for Determining Average Grain Size
• ASTM E165/E165M Standard Practice for Liquid Penetrant Testing for General Industry
• ASTM E1652 Standard Specification for Magnesium Oxide and Aluminum Oxide Powder and Crushable Insulators Used in the Manufacture of Base Metal Thermocouples, Metal-Sheathed Platinum Resistance Thermometers, and*， 2021-11-01 Update
• ASTM E220 Standard Test Method for Calibration of Thermocouples By Comparison Techniques
• ASTM E230/E230M Standard Specification for Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples*， 2023-11-01 Update
• ASTM E235 Standard Specification for Thermocouples, Sheathed, Type K, for Nuclear or for Other High-Reliability Applications
• ASTM E3 Standard Practice for Preparation of Metallographic Specimens
• ASTM E344 Terminology Relating to Thermometry and Hydrometry*， 2023-12-01 Update
• ASTM E45 Standard Test Methods for Determining the Inclusion Content of Steel
• ASTM E585/E585M Standard Specification for Compacted Mineral-Insulated, Metal-Sheathed, Base Metal Thermocouple Cable
• ASTM E780 Standard Test Method for Measuring the Insulation Resistance of Sheathed Thermocouple Material at Room Temperature
• ASTM E839 Standard Test Methods for Sheathed Thermocouples and Sheathed Thermocouple Material
• ASTM E883 Standard Guide for Reflected-Light Photomicrography

ASTM E235/E235M-19 history

• 2023 ASTM E235/E235M-23 Standard Specification for Type K and Type N Mineral-Insulated, Metal-Sheathed Thermocouples for Nuclear or for Other High-Reliability Applications
• 2019 ASTM E235/E235M-19 Standard Specification for Type K and Type N Mineral-Insulated, Metal-Sheathed Thermocouples for Nuclear or for Other High-Reliability Applications
• 2018 ASTM E235/E235M-12(2018) Standard Specification for Type K and Type N Mineral-Insulated, Metal-Sheathed Thermocouples for Nuclear or for Other High-Reliability Applications
• 2012 ASTM E235/E235M-12 Standard Specification for Type K and Type N Mineral-Insulated, Metal-Sheathed Thermocouples for Nuclear or for Other High-Reliability Applications
• 2006 ASTM E235-06 Standard Specification for Thermocouples, Sheathed, Type K and Type N, for Nuclear or for Other High-Reliability Applications
• 2003 ASTM E235-03 Specification for Thermocouples, Sheathed, Type K and Type N, for Nuclear or for Other High-Reliability Applications
• 1988 ASTM E235-88(1996)e1 Standard Specification for Thermocouples, Sheathed, Type K, for Nuclear or for Other High-Reliability Applications